The CO chemical laser has been precluded from consideration as a high-energy laser because of sealing difficulties associated with the production of large quantities of atomic oxygen. The recent development disclosed in U.S. Pat. No. 4,131,863 of the chain-reaction CO chemical laser fueled with CS, CS.sub.2, and O reduces, but does not obviate, the requirement for the chain initiators O and/or S. U.S. Pat. No. 4,115,168 discloses a method of producing CS for the CO chain-reaction laser from a thermochemical combustor fueled with C.sub.2 N.sub.2 --O.sub.2 --CS.sub.2. This invention is concerned with an improved method of producing CS from a thermochemical generator fueled with NF.sub.3 --CH.sub.4 --H.sub.2 --CS.sub.2 that also produces sufficient S to initiate the CS--O.sub.2 chain, thereby allowing for the development of a combustion-driven CO chemical laser of any desired output power.
The chemistry of the CO chemical laser involves many reactions, but the basic reaction sequence consists of the following three steps.
(1) CS.sub.2 +O.fwdarw.CS+SO PA1 (2) CS+O.fwdarw.CO+S PA1 (3) S+O.sub.2 .fwdarw.SO+O.
In the conventional cw CO laser fueled with CS.sub.2, these reactions produce approximately one CO molecule for every O atom supplied to the reaction zone. Since no practical technique for producing large quantities of atomic oxygen has been found, the CO chemical laser has remained a laboratory device.
By fueling the CO laser directly with CS in the chain-reaction laser, reaction (1) is bypassed, and one O atom produces many CO molecules through a chain reaction consisting of reactions (2) and (3). The CS molecule is, however, unstable and produces CS.sub.2 from a heterogeneous reaction. Any residual CS.sub.2 acts as a chain terminator through reaction (1) so that O atoms must still be supplied to the laser. In U.S. Pat. No. 4,131,863 which discloses the chain-reaction laser, CS was produced from the thermal dissociation of CS.sub.2 in an electrical furnace, and O was produced from the dissociation of O.sub.2 in a microwave discharge. The CS furnace produced CS/CS.sub.2 ratios near 1.6 which resulted in approximately 10 CO molecules for each O atom. Such a device is not particularly suitable for scaling. However, by fueling the laser with CS and S from a thermochemical generator, a CO chemical laser unrestricted in power is possible. For this purpose, the NF.sub.3 --CH.sub.4 --H.sub.2 --CS.sub.2 -fueled combustor offers several advantages over the C.sub.2 N.sub.2 --O.sub.2 -fueled combustor previously reported: (1) the side product HF is expected to be less detrimental to laser performance than the CO from the C.sub.2 N.sub.2 --O.sub.2 flame, (2) NF.sub.3 is less toxic than C.sub.2 N.sub.2, (3) the use of CH.sub.4 --H.sub.2 permits optimization of the CS and S production by variation of the carbon-sulfur stoichiometry.
The present invention comprises a high power CO chemical laser which uses CS as fuel and S atoms in a chain reaction so that all of the CS is converted to excited CO. The S-atom chain initiators are thermochemically produced and the laser utilizes air as the oxidizer/diluent. The laser also utilizes a high pressure in the laser cavity compared to other gas lasers.